1. Field of the Invention
The present invention relates generally to magnetic heads for hard disk drives and particularly to magnetic heads having magnetic poles that are formed with a varied nickel-iron alloy composition.
2. Description of the Prior Art
Magnetic heads are generally fabricated utilizing photolithographic, electroplating and thin film deposition techniques to create magnetic shields, magnetic poles and other components on an upper surface of a wafer substrate. In fabricating the magnetic poles utilizing electroplating techniques, a seed layer is first deposited upon a surface of the head, typically utilizing sputter deposition techniques, followed by the fabrication of a patterned photoresist layer, followed by the electroplating of NiFe magnetic pole material upon exposed portions of the seed layer. The magnetic poles are generally composed of a NiFe compound, and it is well known that altering the ratio of Ni and Fe within the pole material will alter the magnetic properties of the pole. For instance, NiFe 80/20 (permalloy) is generally suited best for the main portions of magnetic poles, while NiFe 45/55 is a preferable composition for the portions of the P2 pole tip and of the P1 pole that are disposed adjacent each other with the write gap layer therebetween. Thus, it is known in the prior art to fabricate magnetic poles having separate segments which are composed of NiFe 80/20 and NiFe 45/55.
Where two pole segments composed of NiFe 80/20 and NiFe 45/55 are desired in a magnetic pole, two separate electroplating steps are conducted in which two separate plating baths are utilized, each having a different chemical makeup. Thus, in fabricating such magnetic poles, the first NiFe segment is fabricated in a first electroplating step utilizing the first plating bath, and the second segment is next fabricated in a second electroplating step utilizing the second plating bath.
A need therefore exists for a simplified magnetic pole fabrication method for creating magnetic poles having a varied NiFe ion concentration ratio. The improved magnetic head of the present invention includes magnetic poles having a graduated NiFe ion concentration ratio, in which the poles are fabricated in single electroplating steps, as is described in detail herebelow.